B9 (Human transport) Flashcards
Function of the circulatory system
supplies oxygen and nutrients to the different parts of the body and removes carbon dioxide and other waste material
What is the circulatory system
A system of blood vessels with a pump and valves that ensure one way flow
What does the circulatory system consist of?
A pump (the heart)
blood vessels to carry blood
valves to make sure that the blood flows in one direction only
what do veins do?
carry blood towards the heart
What are the three main blood vessels
arteries
veins
capillaries
what do arteries do?
carry blood away from the heart
What do capillaries do?
connect to the veins and arteries
site of exchange of oxygen, nutrients and waste products
What is blood that is low in oxygen called
deoxygenated (usually denoted w/ colour blue)
What is blood that is high in oxygen called
oxygenated (usually denoted w/ red)
features of veins
-cell layers have less muscle
-fairly thin outer wall
-lumen is wide
-blood pressure is lower
-contains valves (prevent back flow)
features of arteries
-artery wall made of many cell layers (thick)
-lumen is narrow- guarantees high blood pressure
-thick layers of muscle
-muscle cells contract & relax
features of capillaries
-wall made of a single layer of cells
-lumen wide enough to fit ONE RBC
What does single circulation mean?
Single circulation is a type of blood flow where blood passes through the heart only once during each complete circuit of the body.
e.g fish
what does double circulation mean?
blood flows through the heart twice and follows two circuits
e.g humans and other mammals
what are the two circuits that are followed
in the first circuit, the blood flows from the heart to the lungs for oxygenation and then back to the heart
in the second circuit, the blood flows from the heart to the other parts of the body and then back to the heart.
whats the pathway taken by the blood in double circulation?
oxygen diffuses into the blood->
oxygenated blood is carried to all cells in body from the left side of the heart->
oxygen diffuses from the blood to the cells->
Deoxygenated blood is returned to the right side of the heart->
deoxygenated blood is carried to the lungs
what is the pulmonary circuit
the part of the circulatory system that carries blood from the heart to the lungs and back, for gas exchange (oxygen in, carbon dioxide out).
in single circulation, blood flows from the ______ to the _______ to the tissues and cells of the body
heart
gills
what are some structures in the mammalian heart
Muscular wall
Septum
Left ventricle
Right ventricle
Right atrium
Left atrium
One-way valve
Coronary artery
Vena cava
Pulmonary artery
Pulmonary vein
advantages of double circulatory system
-the higher the pressure, the greater the flow of blood and the further the blood can travel in the body
-oxygen and glucose for respiration are supplied rapidly to the cells in the body and waste is removed quickly from them
-blood can be supplied to distant parts of the animals
-near constant body temperature (flow of warm blood)
What are the right and left atrium?
Upper chambers of the heart
What are the right and left ventricles?
Lower chambers of the heart
What do the walls of the heart consist of?
muscle
What is the heart separated by?
The septum
What are the two types of one way valves
where blood leaves an atrium and enters a ventricle.
where blood leaves a ventricle towards the lungs or towards the body.
Blood is pumped away from the heart in ______ and returns towards the heart in ______
arteries
veins
How is the activity of the heart monitored accurately?
with an electrocardiogram (ECG)
how do you record an ECG
small electrodes are fastened over the heart amd other areas of the body
activity is recorded and represented in the form of a graph called an electrocardiogram
What is a pulse
a feeling near the surface of the skin- caused by the expansion and recoil of an artery due to the pressure of blood pumped from the heart
What happens in a heartbeat?
Blood flows from veins into the atria.
atria contracts
blood is pumped into the ventricles
atrial pressure decreases
valves between the atria and ventricles close
backflow of blood to the atria is prevented
ventricles contract
blood is pumped into the arteries
ventricular pressure decreases
valves between the arteries and ventricles close
backflow of blood to the ventricles is prevented
which arteries supply blood to the heart itself?
coronary arteries
what happens if a coronary artery gets blocked?
the cardiac muscles that depend on it cannot produce enough energy for contraction.
as a result the heart muscle will be damaged and may die due to lack of blood supply
What do coronary arteries supply cardiac muscles with
constant supply of nutrients and oxygen as muscles are thick and active and need to contract
What is coronary heart disease?
The disease that arises when the coronary arteries are unable to supply oxygen rich blood to the heart muscles due to blockages in them
what are risk factors (increase the chance)
-age
-diet
-genetics
-gender
-smoking
-stress
what can decrease the risk of CHD
balanced diet and exercise
what happens to heart rate with exercise?
increases
__________ carry blood away from the heart, dividing again and again. Ultimately tiny blood vessels called __________ are formed. The __________ then join up with one another to form large vessels called ________. ________ carry blood towards the heart.
arteries
capillaries
capillaries
veins
what is deoxygenated blood carried in?
veins
(moves into heart and into lungs to be oxygenated)
What is oxygenated blood carried in?
arteries
(moves away from heart to the rest of body)
What happens after blood is oxygenated in the lungs?
Oxygenated blood is carried by the pulmonary veins to the left side of the heart (left atrium). From there, it’s pumped into the left ventricle, and then out to the rest of the body through the aorta- then arteries
Does deoxygenated blood in veins go to the right side of the heart and then to the lungs?
Yes. Deoxygenated blood from the body returns to the right side of the heart (specifically the right atrium) via the vena cava. It is then pumped to the lungs through the pulmonary artery to pick up oxygen.
in capillary, blood cells flow in a _______ ______
single file
smallest lumen?
capillary
valves only in?
veins
why does blood flowing out the heart enter the arteries at high pressure
because of the contractions of the muscular ventricles.
what do arteries contain?
elastic tissues that respond to the rhythmic changes in blood pressure.
What do the thin walls of the capillaries allow
the exchange of nutrients and oxygen
what is the pressure of blood in the veins? what feature allows this?
low
thin walls and a large lumen.
What do valves ensure
the flow of blood is always towards the heart.
why does blood get deoxygenated as it flows through the capillary bed?
oxygen diffuses out of the capillary into the surrounding cells and carbon dioxide enters the capillary from the surrounding cells.
what blood vessel reaches the heart from the lungs
pulmonary vein
what blood vessel reaches the heart from the body
vena cava (vein)
what blood vessel enters the lung from the heart
pulmonary artery
what blood vessel reaches the body from the heart
aorta (artery)
What blood vessel enters the lungs
pulmonary artery
What blood vessel reaches out of the lung
pulmonary vein
which atrium has deoxygenated blood flowing through the vena cava?
right atrium
which atrium has oxygenated blood flowing through the pulmonary vein?
left atrium
the left atrium is actually on the ________ of the diagram and the right is on the ________
left
right
what does pulmonary artery carry
deoxygenated blood to the lungs
what are the components of blood
plasma
platelets
red blood cells
white blood cells
What is plasma
a watery fluid which transports blood cells, ions, soluble nutrients, hormones and carbon dioxide in the blood
What are hormones
A substance, produced by a gland and carried by the blood, which alters the activity of one or more specific target organs.
what are platelets
fragments of cells that are involved in clotting, for example, if the skin is damaged and bleeding begins
What are red blood cells
Type of animal cell that contains haemoglobin, and which transports oxygen around the body.
What are white blood cells
A plasmid containing a foreign gene or sequence of DNA.
RBC function
transport oxygen in blood
what do the biconcave shape of RBCs allow
provides a large surface area compared to the volume, increasing the rate at which oxygen diffuses in and out of the cell.
helps them to bend and squeeze through the smallest capillaries
What do the thinness of the walls in RBCs mean
oxygen only has to diffuse a very short distance to reach the centre of the cell.
What do mature RBCs not have? what does this adaptation allow
no nucleus
provides space to contain many haemoglobin molecules.
What is haemoglobin
a protein that gives red cells their colour (and so the colour of blood). It combines with oxygen when oxygen levels are high, and releases it when oxygen levels are low.
what are features of white blood cells
have large, lobed nucleus
almost colourless
a part of the bodys immune system
What can certain types of white blood cells do
ingest and destroy pathogens (process called phagocytosis) or can produce antibodies
What are pathogens
A disease-causing agent such as a virus or a bacterium.
What is phagocytosis
The process by which a white blood cell engulfs and digests a pathogen.
What are phagocytes
cells involved in phagocytosis
What are lymphocytes
cells involved in antibody production
what are antibodies
A protein produced in the immune system that attaches to antigens carried by disease-causing organisms.
how does blood clotting help
prevention of blood loss and the prevention of pathogens entering the body.
what’s blood composed of
plasma as well as cells
